1. Field of the Invention
This invention relates to a treating device for preventing scattering or similar phenomenon of developer in an electrophotographic copying machine, and more particularly to a device for preventing scattering of developer in the developing device or the cleaning device of the electrophotographic copying machine.
2. Description of the Prior Art
The developing device of the electrophotographic copying machine, as is well-known, is a device for developing electrostatic latent images formed on a photosensitive medium into visible images by the use of developing dust (toner) or a developer consisting of a suitable mixture of toner and carrier. In such a developing device wherein, for example, developing dust is magnetically attracted to the surface of a developing roller and then applied to the surface of a photosensitive drum, the developing dust tends to be entrained by an air stream resulting from rotation of the photosensitive drum and the developing roller and thereby scattered or suspended into the copying machine through the edge of the opening in the developing device. This may result in contamination of the machine interior by the developing dust, or deposition of the dust on the corona wire of the charger which would cause irregular charging effect, or deposition of the developer dust on transfer paper or the photosensitive drum surface which would deteriorate the quality of the resultant image. The dust deposited on the charger would also result in abnormal discharging thereof which might damage the photosensitive drum surface. Such adverse effects of the scatterd toner are more likely to to occur with a increase in copying speed.
As means for preventing such scattering of developing dust, a device using a suction blower and a dust collecting filter to evacuate and collect the developing dust is known from, for example, Japanese Utility Model Publication No. 48/25136.
The conventional device of this type has encountered not only a problem of arrangement in that the device must be mounted in a limited space within a copying machine, but also problems such as the noise which is continuously made by the device, unavoidable complication and higher cost of the device, and reduced efficiency of dust collection which would arise unless filter replacement is frequently made.
U.S. Pat. No. 2,551,582 discloses prior art which adopts the mist developing on a web-like photoconductor, a series of staggered baffles are provided to shield the path of the mist from the optical section. This device is intended to collect droplets falling against the flow of the mist, and tends to be structurally complicated unlike a mechanism which positively utilizes the flow of developer to prevent scattering of toner or the like. No arrangement has been disclosed as yet in which such baffles are disposed as near the surface of the photosensitive medium as possible and yet maintained at that position.